Mary Steenburgen heads to '30 Rock'

When
"30 Rock" heads back to NBC after its extra-long,
Tina Fey pregnancy-accommodating hiatus, there'll be a new face on board.

Mary Steenburgen has signed on to play the mother of
Elizabeth Banks' character,
reports Entertainment Weekly. Steenburgen will stick around for multiple episodes as Charlotte, Avery's "highly spirited and attractive mother."